The patch titled
Subject: mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
has been removed from the -mm tree. Its filename was
mm-compaction-stop-isolation-if-too-many-pages-are-isolated-and-we-have-pages-to-migrate.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
In isolate_migratepages_block, if we have too many isolated pages and
nr_migratepages is not zero, we should try to migrate what we have without
wasting time on isolating.
In theory it's possible that multiple parallel compactions will cause
too_many_isolated() to become true even if each has isolated less than
COMPACT_CLUSTER_MAX, and loop forever in the while loop. Bailing
immediately prevents that.
[vbabka@xxxxxxx: changelog addition]
Link: https://lkml.kernel.org/r/20201030183809.3616803-2-zi.yan@xxxxxxxx
Fixes: 1da2f328fa64 (“mm,thp,compaction,cma: allow THP migration for CMA allocations”)
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/compaction.c~mm-compaction-stop-isolation-if-too-many-pages-are-isolated-and-we-have-pages-to-migrate
+++ a/mm/compaction.c
@@ -817,6 +817,10 @@ isolate_migratepages_block(struct compac
* delay for some time until fewer pages are isolated
*/
while (unlikely(too_many_isolated(pgdat))) {
+ /* stop isolation if there are still pages not migrated */
+ if (cc->nr_migratepages)
+ return 0;
+
/* async migration should just abort */
if (cc->mode == MIGRATE_ASYNC)
return 0;
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
